Systematic review of the long-term effects and economic consequences of treatments for obesity and implications for health improvement

• Published in: Health technology assessment (Winchester, England) England), 2004-05, Vol.8 (21), p.iii-iv
• Main Authors: Avenell, A, Broom, J, Brown, T J, Poobalan, A, Aucott, L, Stearns, S C, Smith, W C S, Jung, R T, Campbell, M K, Grant, A M
• Format: Article
• Language: English
• Subjects: Anti-Obesity Agents - therapeutic use; Behavior Therapy; Caloric Restriction; Cost-Benefit Analysis; Cyclobutanes - therapeutic use; Diet, Fat-Restricted; Humans; Hypoglycemic Agents - therapeutic use; Lactones - therapeutic use; Markov Chains; Metformin - therapeutic use; Obesity - economics; Obesity - mortality; Obesity - therapy; Physical Fitness; Randomized Controlled Trials as Topic; Risk Factors
• ISSN: 1366-5278; 2046-4924; 1366-5278
• DOI: 10.3310/hta8210

To undertake a systematic review of the long-term effects of obesity treatments on body weight, risk factors for disease, and disease. The study encompassed three systematic reviews that examined different aspects of obesity treatments. (1) A systematic review of obesity treatments in adults where the methods of the Cochrane Collaboration were applied and randomised controlled trials (RCTs) with a follow-up of at least 1 year were evaluated. (2) A systematic epidemiological review, where studies were sought on long-term effects of weight loss on morbidity and/or mortality, and examined through epidemiological modelling. (3) A systematic economic review that sought reports with both costs and outcomes of treatment, including recent reports that assessed the cost-effectiveness of pharmaceutical and surgical interventions. A Markov model was also adopted to examine the cost-effectiveness of a low-fat diet and exercise intervention in adults with obesity and impaired glucose tolerance. The addition of the drugs orlistat or sibutramine was associated with weight loss and generally improved risk factors, apart from diastolic blood pressure for sibutramine. Metformin was associated with decreased mortality after 10 years in obese people with type 2 diabetes. Low-fat diets were associated with continuing weight loss for 3 years and improvements in risk factors, as well as prevention of type 2 diabetes and improved control of hypertension. Insufficient evidence was available to demonstrate the benefits of low calorie or very low calorie diets. The addition of an exercise or behaviour programme to diet was associated with improved weight loss and risk factors for at least 1 year. Studies combining low-fat diets, exercise and behaviour therapy suggested improved hypertension and cardiovascular disease. Family therapy was associated with improved weight loss for 2 years compared to individual therapy. There was insufficient evidence to conclude that individual therapy was more beneficial than group therapy. Weight lost more quickly (within 1 year), from the epidemiology review, may be more beneficial with respect to the risk of mortality. The effects of intentional weight loss need further investigation. Weight loss from surgical and non-surgical interventions for people suffering from obesity was associated with decreased risk of development of diabetes, and a reduction in low-density lipoprotein cholesterol, total cholesterol and blood pressure, in the long term. Ta